Apparatus for introducing fluid into subsurface formations



N. A. NELSON APPARATUS FOR INTRODUCING FLUID July 21, 1953 u INTO SUBSURFACE FORMATIONS Filed Dec. 14, 1950 2 Sheets-Sheet l //v VEN TOR. Norman A.Nelson, B X M 1 M I, FIG 2.

ATTORNEX y 21, 1953 N. A. NELSON 2,646,123

APPARATUS FDR INTRODUCING FLUID INTO SUBSURFACE FORMATIONS 2 Sheets-Sheet 2 Filed Dec. l4, 1950 Xxiib) 7x FIG. 9.

nvmvrox v Norman A.Nelson,

A TTORNEY.

FIG. 8.

Patented July 21, 1953 UNITED STATES PATENT OFFICE APPARATUS FOR TRODUCING FLUID INTO SUB SURFACE FORMATIONS Norman A. Nelson, Houston,-Tex., assignor, by 1 mesne assignments, to Standard Oil Development Company, Elizabeth, N. J., a corporation of Delaware Application December 14, 1950, Serial-N0. 200,769 2 Claims. (01. 166-1) 1 r The present invention relates to the treatment of subsurface formations penetrated by a borehole; More particularly, the present invention relates to an apparatus for introducing measured quantities of a fluid into a well bore, particularly those drilled for oil and gas, through a tubin string.

In the drilling of boreholes .into subsurface mentinto the surrounding formation or intothe space between the casing and the borehole walls, the cement slurry is followed up with a nonhardening fluid such as water, pressure being supplied at the surface of the earth to the water to move the cement into the desired position.

In still another instance, a resin-forming liquid is'introduced into the borehole through the; tub ing string after which it is forced into its desired position by means of a non-hardening'fluid, such as water, after which the resin-forming liquid is allowed to set to a hardened mass. 1

It is often desirable that the quantityof fluid introduced into the borehole through thetubing string be known with exactitude. In past field practice, this has not always been possible due to the method by which the fluid has been introduced into the borehole and also due to lack of eifective means either at the surface of the earth or in the borehole for measuring volumetric quantities accurately. The inaccuracies encountered in the field are particularly exaggerated when it is attempted to introduce small quantities of fluid.

The principal object of the present invention is to provide a method and'apparatus for introducing known quantities of fluid materials into boreholes drilled into subsurface formations: A

' further object is to provide a method and means for introducing fluids into theborehole through the tubing string. I

Briefly, the present method may be described as involving the steps of introducing into the borehole a tubular sleeve having a stop therein arranged to permit the passage of fluid therethrough longitudinally of the sleeve, the sleeve being-anchored against longitudinal movement 2, within the borehole. A string of tubing is lowered intothe anchored sleeve until the lower end of the tubing abuts on the stop carried-in the sleeve. A piston-like plug, preferably carrying a resilient sealing material on its outer cylindrical surface, is introduced into the upper end of the tubing, This plug is so designed that it can be pumped down the tubing in contact with ,the

inner walls thereof, the: outer walls of the plus I forming a fluid-tight seal with the inner walls of. the tubing. After the plug is introduced into the tubing, the fluid'which it is desired to introduce into the borehole in measured quantity is pumped into the tubing above the plug, thus forcing the plug downwardly within the tubing. Introduction of fluid into the tubing is continued until a desired quantity has been introduced thereto or until the plug reaches the stop in the tubular sleeve, at which time another plug is introduced .into the tubing. With the first plug closing, 01f,

the lower end of the tubing no further quantity of fluid can be introduced into the tubing until this plug is removed. In order to accomplish rejection of this plug from the lower end of the tubing, the tubing string is raised sufficiently to permit the plug to be forced out the lower end thereof, at which time pressure is applied above the upper plug. This pressure may be exerted by pumping additional similar fluid into the tubing above the second plug or by pumping a dissimilar fiuid into the tubing above the second plug, a sufiicient quantity of fluid being introduced above the second plug to force the second plug downwardly in the tubing to the lower end thereof, at whichtime it will abut against the stop in the sleeve and close off the lower end of the tubing. With the lower end of the tubing string closed off, the pressured-n the tubing builds up indicating to the operator that the plug has reached the lower end-of the tubing. Thus the operator knows that all the fluid between the two plugs has been, introduced into the borehole.

The second plug can be forced from the lower end of the tubing by raising thev tubing slightly and applying pump pressure. When the lastplug has been forced out of the tubing, pressure can be applied to the fluidintroduced into the borehole,

if desired.

The apparatus of the present invention may be briefly described as consisting of a tubular sleeve having a stop positioned therein arranged to permit the passage of fluid therethrou'gh'longitudinally of the sleeve, a tubular member connectiblewith the tubing string inlongitudinal alignment therewith, the tubular member being longitudinally movable in said sleeve, and a resilient piston-like plug arranged in said tubing string for longitudinal movement within said tubular member in sealing type relation with the inner surface of the tubing string and the tubular member. The piston-like plug is arranged to close off the lower end of the tubular member when said lower end abuts against the stop in the tubular sleeve and to be ejected from the lower end of the tubular member when said tubular member is moved away from said stop.

The invention is further described hereinafter and is illustrated in the accompanying drawings in which Fig. 1 is a vertical section of one embodiment of the device of the present invention shown in operative position in a cased borehole;

Fig. 2 is a detail view of a portion of the device shown in Fig. 1;

Fig. 3 is a view taken along the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary sectional view showing the operation of the plug retaining flaps of the present invention;

Fig. 5 is a vertical sectional view of another embodiment of the apparatus of the present invention;

Fig. 6 is a vertical sectional view of another embodiment of the apparatus of the present invention; V

Fig. 7 is a fragmentary sectional view of another embodiment of the apparatus of the present invention;

Fig. 8 is a fragmentary sectional view of a detailed embodiment of the apparatus of Figs. 1 to 4 of the present invention; and

Fig. 9 is a top View of the perforated stop plate shown in Fig. 8.

Referring to the drawings. likenumerals designate similar parts throughout. In Figs. 1, 2 and 3 the device of the present invention is designated by the letter A, the remainder of the structure being included to illustrate the manner in which said device is used and to illustrate the practice of the present invention.

Referring to Figs. 1, 2, 3 and 4, borehole I is drilled into the earth H, the borehole being provided for a major portion of its extent with casing 12 cemented in place with cement l3. Attached to the top of casing I2 is a casinghead M which may be provided with valve connections l and I6, respectively, leading to the interior of the casing. The string of tubing passes through casinghead l4 and extends downwardly within casing |2. If the well is under pressure, it will be necessary to provide a fluidtight seal between tubing string I1 and casinghead l4; a blowout preventer |4' afiixed to casinghead l4 and capable of closing around tubing string ll in fluid-tight relation may be used for this purpose. Gate valve I8 is provided in tubing string above casinghead l4, a clear passage being provided through gate valve l8, when the valve is open, having a diameter at least equal to the diameter of the interior of the tubing. An additional section l9 of the tubing string connects with valve l8 and extends upwardly therefrom, the upper end 20 of tubing section |9 being provided with a removable .closure cap 2 The space within tubing section l9 between gate valve 18 and closure plate 2| may be regarded as a lock chamber 22. Cond'uit 23 controlled by valve 24 fluidly connects with chamber 22 while conduit '25 containing valve 26 also fluidly connects with chamber 22.

4 Conduit 21 fluidly connects valves 24 and 25 while conduit 28 containing valve 29 fluidly connects with conduit 21. An additional conduit containing valve 3| also fluidly connects with chamber 22.

A sleeve member 32 is anchored within casing H by a suitable means as by means of slips 33. As is shown, sleeve 32 is concentrically arranged within casing |2. In the embodiment shown in Fig. l, the lower end 34 of sleeve 32 is shown as being suspended above the bottom 35 of borehole I0, a packer 36 being provided between sleeve 32 and casing |2 to prevent the passage of fluid through the annular space between the outer surface of sleeve 32 and the inner surface of casing l2.

The upper end 31 of sleeve 32 is closed by means of closure cap 38 which defines a central opening 39 extending through said cap. An annular recess 40 opens into opening 39, a suitable sealing means 4|, such as an O-ring, being positioned within annular recess 40.

Disposed within sleeve 32 is a transversely extendin stop 42 afiixed at its outer periphery to the inner surface 49 of sleeve 32, said stop defining a plurality of passages 43 adjacent its outer periphery and a centrally disposed passageway 42'. Perforated sleeve 44 is arranged concentrically within sleeve 32, the upper end 45 of sleeve 44 abutting against the lower surface 46 of cap 38 and the lower end 41 of perforated sleeve 44 abutting against stop 42 and being secured thereto. Openings 43 in stop 42 allow fluids to move longitudinally within sleeve 32 between the annular space formed by the outer surface 48 of perforated sleeve 44 and the inner surface 49 of sleeve 32 and the space 50 within sleeve 32 below stop 42.

Tubular member 5| is threadedly engaged at its upper end 52 with tubing string H, the lower end 53 of tubular member 5| defining a plurality of radially extending projections 54 which fit slidably Within grooves 54 which extend longitudinally of perforated screen 44. Tubular member 5| is arranged to move slidably through opening 39 of closure plate 38, sealing means 4| providing a fluid-tight seal between the outer surface of tubular member 5| and closure plate 38, Projections 54 abut on-the under side 46 of closure plate 38 when tubular member 5| is raised within sleeve 32, thereby limiting the upward movement of tubular member 5| with respect to sleeve 32. In Fig. 1 the lower end 53 of tubular member 5| is shown as abutting against stop 42. A resilient piston-like plug 56 is disposed inside tubular member 5|, the outer cylindrical surface of said plug being in fluid-tight relation with the inner surface of said tubular member, the lowermost face 51 of plug 56 being in contact with stop 42.

A plurality of plu retainer flaps 8|] are positioned in openings 60' of perforated sleeve 44. Flaps 50 are pivotally connected at their upper end to sleeve 44 by pins 6| and their lower end is biased inwardly by spring 61. Flaps 69 are radially spaced from the longitudinally extending grooves 54. The function of flaps 60 is to prevent the re-entrance of resilient pistonlike plug 56 into the interior of tubular member 5| after the plug has been ejected therefrom and after tubular member 5| has been raised Within perforated sleeve 44 so that outwardly extending projections 54 abut against closure plate 38. Thus, each of flaps 6D is pressed by spring 51 through an opening forcing the lower edge 65 thereof into contact with the outer surface of .tubular member 5| along which the flap normal- 1y rides. However, when tubular'member is.

raised within sleeve 32 until outwardly extendingprojections 54 abut against the'under side 46 of closure plate 38, the lower edge 65 of flaps ea cease to ride on the outer surface of tubular member 5|, at which time lower edge 65 extends even further into perforated sleeve 44, all of said flaps cooperating to form a barrier against upward movement of piston-like plug 56 therepast. Flaps 66 are shown most clearly in their plug retaining position in Fig. 4.

Having fully described the embodiment shown in Figs. 1, 2, 3 and 4, its operation will now be described. Cap 2| affixed to tubing extension i9 is removedand a piston-like plug 56 is intro-. duced into chamber 22 after which closure plate 25 is again secured to tubular extension I 9. Dur:-. ing the introduction of plug 56 into chamber 22, ate valve I8 and valve 29 are closed and valve 3| is opened, valve 3| being in the open position; anyfluid trapped in chamber 22 may thus escape therefrom. After plug 56 has been introduced into chamber 22, valves (Hand 26 are closed and valves i8, 24, and 29 are opened. The fluid material which is to be delivered to borehole 6 in definite volume is introduced into tubing I7 and tubular member 5| by pumping the fluid into chamber 22 above plug 56 through conduit 23 controlled by valve 29'. The introduction of fluid into chamber 22 above plug 56 causes, of course, plug 56 to descend within tubing ll, After the desired quantity of fluid has been introduced into chamber 22, gate valve l8 and valve 29 are closed, closure plate 2| removed, and a second resilient plug 56' is in-' serted into chamber 22 in the same manner as the first plug 56 was introduced. Closure plate 2| is then replaced and gate valve I8 and valves 24 and 29 are opened. 'A fluid, which may be a fluid similar to that previously introduced or dissimilar to that previously introduced, is then introduced into chamber 22"through conduits 28, 21, and 24. Pump pressure may be indicated by a suitable gauge and, pumping of this fluid I is: continued until the gauge registers a sudden large increase in pressure. This suddenincrease in pressure will occur when plu 56 strikes stop 42 inasmuch as the lower end 53 of tubular mem-' ber 52 is abutting on stop 42 during this pumping operation. At this stage the operator knows that the measured quantity of fluidin tubing andtubular member 5| is now ready to be delivered to the borehole. Delivery of this fluid into the borehole is accomplished by raising tubingll and tubular member 5| a sufficient amount to permit plug 56 to be forced from the lower end 53' of tubular member 5|, thereby permitting the fluid above this plug to escape from the lower end of said tubular, member. The operator will know when plug 56 has been expelled from the lower end 53. of tubular member 5| because the pump pressure will decrease when this occurs. The pipe 5| is raised only member 5| until the 'second resilient- 'plu'g 56-" strikes the. first resilient; plug 56, at which:tuner further downward movement is. prevented. and vfluidiceases to flow downwardly within tubing IT. The lower end'53 of tubular member, ,5| is now closedv by the second resilient plug 56, a condition which is announced to the operator by the increase in pump pressure. in the pump pressure signifies to the operator that all of the fluid between the first and second resilient plugs has been introduced into borehole Ill.

:Fluid'in tubing above the second resilient plug 56', whether it be a fluid similar to the between'the first and second plugs into formation III, a quantity of driving material, such as water, "may' be introduced through tubing string into borehole |0 for accomplishin thlS'Gblective. If it is desired to introduce a definite quantity of the driving fluid, its'volume may also 'be'me'asured in described.

If after introducing a quantity of fluid material, it is desired to -remove the-device ofthe present invention :from the borehole, slips 33 and packer "36 are; disengaged from casing l2. Tub-- ing H is then raised which will, in turn, causetubular member 5| to move upwardly within sleeve 32 .until projections 54 abut against closure cap -38 at which time flaps 66 will pivot about" pins 6|, the lower edge65 of flaps-6|l projecting into the interior of perforated screen 44. pumping a fluid such as drilling mud into the annular'space between tubing l'l-andcasing 2 through conduits l5 or l6, the'fluid so circulated will pass from said annular" space into the interior'of-sleeve 32,"thence through openings 43 in stop 42 and'through the perforations of sleeve 44 into the interior thereof; Since the direction of flow is upward within perforated'sleeve 44,'resilient plugs 56 within said sleeve will tend to move upwardly'but their upward movement will be'limited'by abutment against flaps 60.

enough to allowthe plug 56 to be ejected. .The

Since flaps 60 limit the upward movement of resilient plugs56, the fluid being reverse circulated can flow from the annular space between perforatedsle'eve '44 and sleeve 32 through the perforations of sleeve 44 located below flaps 66 and thence into tubing ll. After reverse circulation is completed, further raising of tubing I'I lifts. the device of the present invention and such lifting may be continued until said device is raised through blow-out preventer l4 and clear of the wellhead.

A more'simplifled form of the apparatus of the present invention than that shown in Fig; l'is illustrated in Fig. 5. Referring to Fig. 5, a

well bore I6 is drilled into the earth bore hole I O'being prov'ided'with casing |2down to' a pointin borehole l0 above subsurface formation In. Casing I2 is shown as cemented in place with cement l3. Attached to the top of casing-l2 is a casinghead 4 having valved connections I5 and I6, respectively, leading to the interior-of the casing, Afiixed to casinghead 4 is a blow-out preventer M; A string of tubing l1 extends through casinghead l4 and blow-out preventer I4 into casing l2, tubin string being arranged to be moved longitudinally in leasing- 2- through casinghead 4 and blow-out This increase he manner hereinbefore.

If it is desired to reverse circulate, as by preventer I4 in fluid-tight relation with blowout preventer I4.. Tubing string I'I, above blowout preventer I4, is provided with a gate valve I8, gate valve I8 having a clear passage therethrough when the valve is open, the passage having a diameter at least equal to that of the internal diameter of the tubing. An extension I9 of tubing II connects with gate valve I8, the upper end of extension I9 being provided with a removable closure plate 2|. The space inside extension I9 between gate valve I8 and removable closure cap 2| will hereinafter be designated as lock chamber 22. Conduit 23 containing valve 24 and conduit 25 containing valve 26 connect with chamber 22. Conduit 21 joins conduit 23, and conduit 25 and conduit 28 containing valve 29 connect with conduit 21. Conduit 28 is connectible to pumps for supplying fluids to be introduced into chamber 22. Conduit 30 containing valve 3| also connects with chamber 22 and may be used as a drain line for said chamber if desired,

A plug stop I0 in the form of a disc or plate having a plurality of openings 'II positioned adjacent its outer periphery and a centrally disposed opening I0 is removably secured to casing I2, as by means of a suitable slip assembly 12. It will be noted that plug stop II! extends across the bore of casing I2 and is substantially perpendicular to the longitudinal axis of said casing.

When it is desired to introduce a measured quantity of a given fluid into the borehole when using the embodiment illustrated in Fig. 5, and assuming that borehole I0 already contains a diflerent fluid, gate valve I8 is closed and valve 3| is opened, permitting fluid to drain from chamber 22 through conduit 30. After chamber 22 has been drained through conduit 30, valve 3| is closed and removable closure plate 2| is removed from the upper end 20 of extension I9. A resilient piston-like plug is introduced into chamber 20, it being pushed into said chamber until its upper edge is below the point at which conduit 23 connects with chamber 22. The introduction of the measured quantity of fluid to be introduced into the borehole is then commenced by pumping said fluid through conduit 28, conduit 21, and conduit 23, valves 29 and 24 being opened and valve 26 being closed during this initial pumping operation. When sufiicient fluid has been introduced into chamber 22 to force the piston-like plug against the upper edge of gate valve I8, this valve is opened to permit passage of said plug therethrough. The introduction of fluid is continued until the desired quantity has been introduced into tubing IT, at which time pumping is discontinued and valve 29 and '24 are closed. Valve I8 is also closed. Valve 31 is opened to permit fluid to drain from chamber 22, after which valve 3| is closed and plate 2| again removed from the upper end 20 of extension H]. A second resilient plug is then introduced into said chamber and is pushed downwardly therein until its lower edge contacts the upper surface of the fluid previously introduced into chamber 22, this upper surface, of course, being on a level with conduit 30. Closure plate 2| is again secured to the upper end 20 of extension I9 and additional fluid, either similar to the fluid previously introduced or dissimilar from said fluid, the choice being with the operator, is introduced into chamber 22 above the piston-like plug through conduits 28, 21, and '23, valves and 29 being opened and valve 26 being closed. When the piston-like plug abuts against valve I8, this valve is opened, permitting the piston-like plug to pass therethrough. If it is desired that the fluid introduced behind the second plug also be introduced in measured quantity and that it be separated from a sumequent slug of fluid, a third piston-like plug may be employed to divide the second and third batches of fluid. It will be understood, of course, that as many different segregated batches of fluid as desired may be introduced into tubing string II. In the drawing, the batches are shown as being separated by plugs I3, I3, and 13''. It will be understood, of course, that as soon as plug I3 is started downwardly in tubing string H by the fluid pressure exerted thereabove, the fluid already present in the borehole will be displaced from borehole III, by the introduced fluid. The displaced fluid can either be forced into formation I0 ahead of the introduced fluid by maintaining valved conduits I5 and I6 closed or it may be permitted to flow upwardly through the annular space between tubing I1 and easing I2 and outwardly of the casing through valve conduits I5 or I6 or both. Fluid introduced under pressure through conduit 28 will continue to force piston-like plugs "I3, I3, and 13" downwardly within tubing I'I until the lowermost of these plugs, namely I3, abuts on plug stop I0. Since the lower edge ll of tubing string I! also abuts on plug stop It, the arrival of pistonlike plug I3 at stop '10 effectively prevents further movement of fluid within tubing IT. This, of course, causes an increase in pressure in tubing I'I, this increase in pressure indicating to the operator that plug I3 has reached stop '10. After noting this increase, the operator then raises tubing string I! a sufficient amount to permit plug 13' to be forced out the lower end ll of tubing IT, at which time the fluid inside tubing I! can flow out the lower end H of said tubing through openings II in plug stop ID into borehole I0. Normal pumping is continued until piston-like plug I3 reaches the lower end ll of tubing IT, at which time piston-like plug 13' abuts against piston-like plug I3, preventing further movement of fluid through tubing I1 and causing another increase in pressure. This increase is noted by the operator who again lifts tubing I'I until plug I3 is forced out the lower end ll of tubing I 'I. With piston-like plug I3 forced out the lower end ll of tubing II, normal pumping can again be resumed, if desired, to deliver the batch of fluid between piston-like plug I3 and piston-like plug 13". This alternate pumping and lifting can be repeated by the operator as many times as is desired until all the introduced plugs have been forced to the lower end H of tubing I1.

Another embodiment of the apparatus of the present invention is shown in Fig. 6. Referring to Fig. 6, a well bore I0 is drilled into the earth II, borehole Ill being provided with casing I2 down to a point in borehole I0 above subsurface formation IIl'. Casing I2 is shown as cemented in place with cement I3. The surface equipment attached to the top of casing I2 is not shown as it is the same as that shown in the previous figures.

A tubing sleeve I0 is arranged concentrically within borehole I0, its upper end IIlI b ing suspended from and secured to casing I2 by means of slips I02. A packer I03 is also provided, the packer closing off the annular space between tom 35. of borehole ill.

posed within tubing ll, longitudinally movable within tubing string l? in sliding and sealing contact with the inner walls thereof'.

. subsurface formation Ill.

sleeve Hi0, and casing I2. The open lower end IM of tubular member Hill is suspended off the bot- A plug stop W is secured within tubular member ml, plug stop I65 being provided with a plurality of openings I66 adjacentits outer periphery and a centrally disposed passageway Hi5. Plugs ill? and Hit are dis- Plugs Hill and IE3 are When it is desired to introduce a known quantity of fluid into the borehole with the embodiment shown in Fig. 6, and assuming the borehole containsanother fluid, such as water, valve conduits l5 and IE are closed off and plug till is inserted in tubing string H. Th fluid to be introduced is then pumped into tubing ll above plug It? and plug llll forced downwardly therein. When the desired quantity of fluid has been bular member is provided with perforations I for the passage of fluidstherethrough. Tubing string ll extends from the surface of the earth into tubular member I20, its lower edge !26 abutting on plug stop I23.

. cal'with that shown in Figs. 1, 2, 3 and 4 except for the design of the plug stop. Referring to Figs. 8 and 9, borehole I!) is providedwith casing I2 cemented in place by means of cement I3. Tubular member 32 is secured in place within casing I2 by means of slips 33 and packer 38. A plug introduced into tubing ll above plug Nil, plug Y use is then inserted and additional fluid introduced above plug ms. The fluid introduced above plug Hi8 may be a fluid similar to that introduced between plugs Ill! and IE8 or it may be a different fluid. In any event, in order to deliver the fluid in tubing ll located between plugs it! and lilil, fluid is introduced into tubing I'I under pump pressure until plug i0? reaches the lower end 609 of tubing ll, said lower end )9 abutting on plug stop M5. When plug IG'l reaches the lower end Ills of tubing ll, it also abuts on stop I05, preventing further movement of fluid within tubing N. This causes a buildup of pressure in tubing ll, this build-up of pressure indicating to the operator that plug it? has reached the lower end 509 of tubing l1. At this stage the operator raises tubing ll until plug Iil'i is expelled from the lower end its thereof, permitting fluid to flow from the interior of tubing I? through openings l 66 and out the lower end Iil l of tubular m mber I 8% into borehole Ill. Fluid will continue to flow from tubing l'I until such time as plug we reaches the lower end Hi9 of said tubing, at which time plug Hi8 will abut against the upper edge I Ill of plug Nil. Again the pump pressure will build up and indicate to the operator that plug I08 has reached the lower end of tubing ll. It will further indicate to the operator that all of the fluid in tubing I? between plugs i0! and 508 I has been delivered to borehole ii]. If the operator desires to deliver additional fluid to borehole ill, tubing I! is again raised and pump pressure applied within tubing I! to xpel plug Hi8 from the lower end thereof.

A variation of the embodiment of Fig. 6 is illustrated in Fig. '7. The only difference in the structure of Fig. 6 and that of Fig. '7 is that the necessity for providing a packer or slips, or both, is eliminated.

Referring to Fig. '7, a well bore it is drilled into the earth Ii, borehole it being provided with casing i2 down to a point in borehole ill above Casing i2 is shown as cemented in place with cement I3. A tubular member .IZfi is lowered within casing I2 and set V in position within borehole I8 with its upper end iZI being positioned above the lower terminus of easing I2. The lower end 122 of tubular member I29 rests on bottom of borehole Ill. Disposed within tubular member l2ii is a plug stop E23 which defines a plurality of openings I24 adjacent the outer periphery thereof and a centrally disposed passageway ltd. Below stop E23 and above the lower end E22 of tubular member I29, said tuto be connected at its upper end to a tubing stop 36 is secured within sleeve 32, plug stop I39 being provided with a plurality of openings I3l adjacent the outer periphery thereof. A central opening I32 extends through plug stop E38. Perforated sleeve A l is disposed within sleeve 32 with its lower edge 4'! abutting on plug stop I30. As will be'noted in Fig. 8, the diameter of opening I32 is less than the internal diameter of sleeve 44. The purpose of providing opening 32 in plug stop I39 is to permit the passage of the balls therethrough, not shown, needed for setting certain well-known commercial packers and slips. After these balls have been passed by plug stop E30 and such packers and slips have been set, a larger ball is introduced, this larger ball being of such size that it will not pass through opening I32. This ball, designated I 33, is also of a, material which is sufiiciently resilient to close off opening I32 and to prevent the passage of fluid therethrough. When ball H33 is used, the first piston-like plug introduced will of course abut against this ball rather than against plug top I 30.

Having fully described the apparatus and method of the present invention, what I wish to claim as new and useful and to secure by Letters Patent is:

l. A device for spotting a fluid material in a well comprising an outer sleeve, a horizontally disposed stop in said sleeve having at least a port adjacent an outer periphery of the stop and a second port in said stop centrally disposed therein for the passage of fluid therethrough, an inner perforated sleeve concentrically arranged within a perforated sleeve and the upper end of said outer sleeve being joined in fluid-tight relation, the lower end of said, perforated sleeve abutting against said stop, and a tubular member adapted string; saidtubular member being slidably arranged in said perforated sleeve for longitudinal movement therein, said tubular member and tubing containing at least one plug slidably arranged therein in fluid-tight relation with the inner surface of said tubular member and tubing.

2. A device'for spotting a fluid material in a well comprising an outer sleeve, a perforated circular plate arranged horizontally in said sleeve having a plurality of ports adjacent an outer periphery of the plate and a second port in said stop centrally disposed therein for passage of fluid therethrough, an inner perforated sleeve concentrically arranged within said outer sleeve to 11 form an annular space between the outer surface of the perforated sleeve and the inner surface of the outer sleeve communicating with said ports, the upper end of said perforated sleeve and the upper end of said outer sleeve 'being joined in fluid-tight relation, the lower end of said perforated sleeve abutting against said plate, and a tubular member defining a lateral stop member with a lower end thereof adapted to be connested at its upper end to a tubing string, said 12 in in fluid-tight relation with the inner surface of said tubular member and tubing.

NORMAN A. NELSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,459,989 Reed June 26, 1923 2,187,480 Baker Jan. 16, 1940 2,223,442 Crowell Dec. 3, 1940 2,335,387 Cantin Nov. 30, 1943 2,481, 122 Haynes et a1. Sept. 6, 1949 2,559,536 Haynes et a1. July 3, 1951 

